New camera, new questions

[+Stu]

Hi. So I've done some reading up on setting up an astro camera and I think I almost get it. 

I was just wondering what a good starting point would be. Just start at zero gain/offset and experiment from there? With clear skies so rare at the moment it'd be good to start off with some decent data. 

[Bob Dobber]

I normally just google and go with whatever the majority suggest. Almost always unity gain in my experience, the "number" for which varies from camera to camera. What camera is it?

 

I did try zero gain on my 533MM (having always used unity gain on previous 533MC's) but it was awful. I am sure someone more scientific will explain why different gains will benefit different targets etc, I should have perservered but given you'll need a dark library for any gain you opt for (as well as life being too short, and clear skies being in too short supply) I find picking one and sticking with it is the best route for me! HTH.  

[+Stu]

Picking one and sticking with it will be best for me as like you say, not a huge amount of time to try different settings. It's a hypercam 269C.

[Bob Dobber]

This table is on the product page, presume you've seen it?

 

 

 

 

[+Stu]

1 hour ago, Bob Dobber said:

This table is on the product page, presume you've seen it?

I did, but I don't really understand what it's telling me in relation to what settings to use. From what I read on various forums/blogs, it sounds like I need to go for a gain setting (around 200-300) then do some experimenting with offset using the histogram to eliminate any zero value pixels. Does that sound about right?

[+Stu]

Ah, so googling the right question results in unity gain being 282 HCG and 564 LCG in ASCOM driver/Sharpcap 👍

Edited May 7, 2023 by Stu

[Bottletopburly]

22 hours ago, Stu said:

Ah, so googling the right question results in unity gain being 282 HCG and 564 LCG in ASCOM driver/Sharpcap 👍

Yes you should use 282 gain as that is the unity for your camera, offset is a funny thing that a lot of people don’t understand me included but I had a look at this yesterday whilst looking into your camera https://daleghent.com/ and you may be able to work out the offset for your camera at 282 Gain if you follow instructions, now I use on my 533mc offset of 10 gain 100 (unity) but looking into the histogram in sharpcap it looks close to the left but trying off set of 15 or 20 moves it slightly away so I may try 20 and shoot a new library of darks and flat darks .

[+Stu]

14 minutes ago, Bottletopburly said:

may be able to work out the offset for your camera at 282 Gain if you follow instructions

Thanks, that article looks very interesting! I'll have a proper look later when the house is a bit quieter. I'm still yet to sit down and have a play with it in Sharpcap. 

Does your camera stay in the same position all the time?

 

I've also been looking at binning. I'm using 1x1 on my DSLR but from what I've read, using 2x2 on the 269C could be beneficial. 

[Bottletopburly]

12 minutes ago, Stu said:

Thanks, that article looks very interesting! I'll have a proper look later when the house is a bit quieter. I'm still yet to sit down and have a play with it in Sharpcap. 

Does your camera stay in the same position all the time?

 

I've also been looking at binning. I'm using 1x1 on my DSLR but from what I've read, using 2x2 on the 269C could be beneficial. 

Just shoot in 1x1 bin in software, you don’t worry about moving camera using darks and dark flats only flats hence time saving 

[Clive]

2 hours ago, Stu said:

... I've also been looking at binning. I'm using 1x1 on my DSLR but from what I've read, using 2x2 on the 269C could be beneficial ....

It really depends on the scope you're pairing it with as it's all about achieving a balance between undersampling and oversampling, both of which should be avoided (another rabbit hole for you to go down ☺). With the 269's 3.3um pixels 2 x 2 binning probably isn't really needed for scopes with a focal length of less than about 1000mm.

[+Stu]

2 hours ago, Clive said:

less than about 1000mm.

Cool, my scope is 560mm so I'll leave it as is.